Posted by
Joachim Wesner on
Jul 18, 2006; 6:45pm
URL: http://imagej.273.s1.nabble.com/Sharpen-Filter-tp3702120p3702122.html
Hi
there is no principal difference, both will in the end enhance higher
spatial frequencies relative to low spatial frequencies,
however sharpening kernels enhance higher spatial frequencies by evaluating
differences between adajacent pixels and
adding a weighted sum to the central pixel, while the unsharp mask first
goes the other way round, it creates an even
less sharp version of the image and calculates a weighted difference to the
original image.
Depending on the weighting parameters, resp. the sharpening or smoothing
kernels used, the different methods will exhibit
different tradeoffs between edge steepness, overshoot etc and noise on the
other hand, that´s the reason the different
methods exist.
Hope this helps
JW
Klughammer GmbH
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18.07.2006 18:59
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Hi,
can anybody explain the difference of the sharpen filter and the unsharp
mask.
Anneliese
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